About - Contact - Motorcycles FS - Parts FS

Home page
^ Back to Home Page ^

Period Roadtests

Article: Performance Bikes - Fast Specials 1993
I still have vivid memories of my 350LC. Like oh-so-nearly wheelying over back wards whilst wearing a canvas rucksack full of highly sharpened chef's knives. Of tankslappers so furious I was sure I'd bro ken my left wrist. Power bands so acute and explosive I was forced to chuckle. But the most vivid memories are the almost daily brushes with the law. Ah, happy days. Come to think of it, I was very lucky to sur vive the experience.

That was 1983 but even today there's no real substitute for the 350LC. Nothing can give you the same kicks for as little money. Yes, the little liquid-cooled Yamahas are still almost unique. Let's call it a very high giggle per £ ratio.

Paul Beaumont is seriously hooked on LCs. This is his ninth in a row and he's already making plans for his tenth. Over that period of time he's tried most things, including radical porting and every go-fast goodie. But now experience has taken him full circle; fed up with cold seizures, holed pistons, wrecked barrels and bent cranks he's gone sensible.


The build theory has been to make it fast but reliable. That's a YPVS motor slotted in a slightly older 350LC chassis - a good way to gain more reliable power. The YPVS motors were much more tractable, too, thanks to Yamaha's power valve system. When the old 350LC motors would be gasping for breath at conservative revs, the powervalve motors pulled cleanly and more crisply. Someone once wrote into the magazine to tell us that YPVS stood for Yemenese People Vomit String, but he obviously hadn't been reading his Haynes manual properly.

The engine was rebuilt by Paul's mate Steve at Track Record in Camberley, to what he describes as a stage I tune. This involves mildly ported barrels (Bob Farnham), a slotted stator plate to optimise the ignition timing, and careful assembly and tolerance checking. To up the sometimes troublesome clutch Steve used three TZ750 and three XJ650 clutch springs. The motor breathes through a standard airbox and standard carbs with 320 main jets. Plugs are NGK BR9EV's and the beautifully-formed exhausts are by Pete Gibson.

But the work didn't just stop at the engine. If anything that was the least of Paul's worries - cycle parts are probably the worse thing about the old LC They've got skinny rims and tyres, troublesome and not paticularly effective brakes, a back shock like a pogo stick and forks that tie themselves in knots. It's no wonder they used to wallow, wobble and weave their way to hell and back.

Paul has had his fair share of these so most of his mods are designed to eliminate errant behaviour. Wider rims (CMA) have allowed the use of modern rubber in modern sizes; the bike now wears lovely sticky Hi-Sport Michelins. Brakes are a combination of Spondon floating rotors (common as muck because they're such good value for money) and twin piston, alloy Lockheed calipers. The master cylinder with the job of looking after this new-found braking power is GSX-R11OO.

Forks are Marzocchis of unknown vintage, purchased from a man in Barrow-in-Furness. I only mentioned Barrow-in-Furness because it doesn't get mentioned very much - there you go, I said it again. Spondon made up the spacers and caliper brackets and bolted the forks into a pair of their adjustable offset yokes. The fork brace was made by an insider at the McClaren Fl team HQ in Sheerwater... how's that for a bit of name dropping?

With the remaining possibilities of a front end wobble kept in control by a White Power steering damper and taper-roller head bearings, Paul's attentions turned to the back end. The standard 350LC swinging arms were so feeble you could bend them in your hands so Paul ordered a JMC item. It took ages to turn up but there's no denying the extra stiffness and it looks the bog's dollocks with its eccentric chain adjusters, nice welds and highly polished, bare alloy finish.

Replacing the standard damper is a White Power shock and spring with remote reservoir - a serious shock with a serious price tag, but infinitely adjustable in every direction. It needed a bit more fiddling with spring preload, or perhaps even a longer, heavier rate spring, to get the rear ride height up a bit. Look at the pictures of the bike from the side and you'll see what I mean: it's about two inches too low at the back end.


It's clear from the almost medical cleanliness of the bike that Paul is a doting, caring and pedantic owner, completely absorbed by the cult of Elsie. Every last nut, bolt, washer and bracket has been scrutinised to the ninth degree. I got the impression that Paul's bedroom doubled as his centrally-heated LC parts department and garage. But he didn't seem to mind too much when I came to ride the bike. His major concern was whether could get to grips with the unfamiliar (to me) down-for-up shift pattern on the home made rearsets.

Thrashing LCs to within an inch of their life is obligatory. There is no other way of riding them. Being out of the powerband is about as much fun as riding a BSA Bantam in winter. They pull OK when they're not in the power but there's no substitute for that front-end- lightening, kick-in-the-pants feeling as they change from Jekyll to Hyde. It's the cause of LC mania. People crave the light-switch transformation at 7,000rpm like Dick Watson craves the day's first Benson the moment his eyes open.

The nicest thing about Paul Beaumont's special is the engine. You could hardly describe a tuned LC as docile, but this one felt refined. Even a lazy prod on the kick- start lever would spark it into life and settle to a reliable tickover, both Gibson pipes crackling away quietly.

A two stroke, any two stroke, is made or broken by its carburation and exhaust taper. Get these wrong and you'll spend your life chucking pistons at the engine like they're going out of fashion. Judging from Paul's bike, Pete Gibson is a man who knows what he's doing, as is Steve Williams from Track Record.

On the move it feels even better. Downshifting throttle blips are super-crisp, with no fluffing or hesitating as can so eas- ily happen. As fast as you can physically open the throttle, it'll respond. The motor pulls harder than it has any right to below the power step, yet the transition between nothing and everything seems to have lost none of its ass-kicking delivery. I found it best to up-shift without the slightly heavy clutch, just to maintain the revs. By my mental dynamometer I'd guess at about 55-60bhp at 10,000rpm. Not drastic power, but drastic power from an LC is usually short-lived.

If you've never ridden an LC or a small, fast two stroke twin you won't appreciate why they are so fast and effective. There's nothing to them - no excess flab, no plethora of moving engine internals; just a real yahoo, yobbish personality. It's great stuff, especially combined with all the mod- ern attributes, like good brakes, good tyres and good suspension.

You can literally hurl it from full left lean to full right. It's not only the lack of weight that helps you do this, but the riding position too. The Spondon clip-ons are mounted right underneath the top yoke, so it's no massive stretch to them. The rearsets tuck your feet up under your bum which is plonked on a sparsely-padded Guiliari seat If you were six foot plus, you'd hate it. You wouldn't be inclined to ride it to the South of France and back, either. Interestingly enough, Paul brought it along in a van.

Today's small two strokes have a lot more engine over the front wheel. Witness on an RGV how close the front spark plug is to the back of the wheel. The LC is from an era before this current thinking; an era where wheelies were more important than anything else. Where front wheels were supposed to aviate coming out of slow, uphill corners. And tankslappers were an integral part of adolescence.

A long ride also explains why LC fanatics even begin to smell the same as their bikes. When you get off the bike, you stink A sickly sweet smell of exotic, synthetic, two stroke oil mixed with heavily-leaded petrol. This stench somehow finds its way into the lining of your helmet, your gloves and your hair. I happen to love the smell of expensive two stroke oil but, like Castrol R, it's not the sort of smell people meet with indifference.

Detail touches abound on the Beaumont Powervalve. The paintwork, applied by John Sherbourne, is a labour of love, T-Cut and Turtle Wax. Many alloy bits are professionally polished and those that aren't have been chromed or powder coat- ed. I dread to think what they'd look like if the bike was ridden round Peterborough's salt strewn roads in winter, but it's not going to. This is a motorcycle for pleasure, for blowing out cobwebs on a Sunday afternoon and generally misbehaving on.

I liked Paul's LC. I'd want to do some suspension twiddling, reverse the gearshift pattern and maybe fit lighter wheels than the CMAs but they're only my personal preferences. As it is, it's just fine.


350YPVS Yamaha. Bob Farnham ported barrels, rebuild by Steve Williams. Slotted stator plate, NGK BR9EV plugs, standard carbs fitted 320 main jets, Pete Gibson exhausts. Three TZ750 and three XJ650 clutch springs, ditched oil pump, stock gears and radiator.


Stock 350LC frame with new engine plates. Marzocchi 37mm forks In Spondon adjustable offset yokes. JMC alloy swinging arm with eccentric chain adjustment. Spondon clipons and Spondon wheel spindles and spacers.

Wheels & Brakes

18in CMA's front and back with Michelin Hi-Sport tyres, 280mm Spondon floating disc rotors and Lockheed calipers with GSX-R11OO master cyinder. Rear disc: 210mm Spondon floater, Brembo caliper and YPVS cylinder.

Cycle Parts

Standard power valve bodywork, tank fitted with Shaw filler cap and extra breather, standard VPVS clocks and headlight. YPVS switch gear and KR-1 front mudgMard, homemade rearsets Incorporating some original parts, heavy duty O ring chain and 38 tooth alloy Renthal sprocket.

If you need work done on your classic machine, from basic service to full rebuilds, contact me, I can help.

Period Roadtests

netbikes is a registered business with the Queensland office of Consumer Affairs.
Business Names Act 1962 - 1990 Section 7 (4) Business # BN5951173
© netbikes Motorcycle ONLY Classifieds Australia
Brisbane 4122 QLD AU Ph. 0422819200